#define _CRT_SECURE_NO_WARNINGS 1

#include "Date.h"

Date::Date(int year, int month, int day)
{
	_year = year;
	_month = month;
	_day = day;

	if (!CheckInvalid())
	{
		cout << "构造日期非法" << endl;
	}
}

bool Date::operator<(const Date& d)const
{
	if (_year < d._year)
	{
		return true;
	}
	else if (_year == d._year)
	{
		if (_month < d._month)
		{
			return true;
		}
		else if (_month == d._month)
		{
			if (_day < d._day)
			{
				return true;
			}
		}
	}

	return false;
}

// d1 <= d2
bool Date::operator<=(const Date& d)const
{
	return *this < d || *this == d;
}

bool Date::operator>(const Date& d)const
{
	return !(*this < d);
}

bool Date::operator>=(const Date& d)const
{
	return !(*this < d);
}

bool Date::operator==(const Date& d)const
{
	return _year == d._year &&
		_month == d._month &&
		_day == d._day;

}

bool Date::operator!=(const Date& d)const
{
	return !(*this == d);
}

Date& Date::operator+= (int day)
{
	_day += day;
	while (_day > GetMonthDay(_year, _month))
	{
		_day -= GetMonthDay(_year, _month);
		++_month;
		if (_month == 13)
		{
			++_year;
			_month = 1;
		}
	}
	return *this;
}

 //d1 + 10
Date Date::operator+(int day)const
{
	//Date tmp(*this);
	Date tmp = *this; // 拷贝构造

	tmp._day += day;
	while (tmp._day > GetMonthDay(tmp._year, tmp._month))
	{
		tmp._day -= GetMonthDay(tmp._year, tmp._month);
		++tmp._month;
		if (tmp._month == 13)
		{
			++tmp._year;
			tmp._month = 1;
		}
	}

	return tmp;
}

// d1 += 100
//Date& Date::operator+=(int day)
//{
//	*this = *this + day;// 赋值
//
//	return *this;
//}

Date Date::operator-(int day)const
{
	Date tmp = *this;
	tmp -= day;

	return tmp;
}

Date Date::operator-=(int day)
{
	_day -= day;
	while (_day <= 0)
	{
		--_month;
		if (_month == 0)
		{
			--_year;
			_month = 12;
		}

		_day += GetMonthDay(_year, _month);

	}

	return *this;
}

//++d ->d.operator++()
Date& Date::operator++()
{
	*this += 1;
	return *this;
}

//d++ -> d.operator(0)
Date Date::operator++(int)
{
	Date tmp = *this;
	*this += 1;
	return tmp;
}

//--d ->d.operator++()
Date& Date::operator--()
{
	*this -= 1;
	return *this;
}

//d-- -> d.operator(0)
Date Date::operator--(int)
{
	Date tmp = *this;
	*this -= 1;
	return tmp;
}

// 日期-日期 返回天数
	//法1：年-年，月-月，日-日，太过复杂
	//法2：找出较小的那个，一直累加直到等于大的那个，累加的次数就是之间的天数
// d1 - d2
int Date::operator-(const Date& d)
{
	//找出较小的那个日期，这里先假设*this较小
	Date min = d;
	Date max = *this;
	int flag = 1; //用于表示最后相减结果的符号
	if (*this < d) //假设不成立，互换
	{
		min = *this;
		max = d;
		flag = -1;
	}

	//小的进行累加，直到二者相等
	int ret = 0; //统计min累加的次数
	while (max != min)
	{
		min++;
		ret++;
	}
	return ret * flag; //最终累加的次数即为日期差
}

bool Date::CheckInvalid()const
{
	if (_year <= 0 || _month < 1 || _month > 12 || _day < 1 || _day > GetMonthDay(_year, _month))
	{
		return false;
	}
	else
	{
		return true;
	}

}
ostream& operator<<(ostream& out, const Date& d)
{
	out << d._year << "年" << d._month << "月" << d._day << "日" << endl;
	return out;
}

istream& operator>>(istream& in, Date& d)
{
	while (1)
	{
		cout << "请依次输入年月日:>";
		in >> d._year >> d._month >> d._day;
		if (!d.CheckInvalid())
		{
			cout << "输入了无效日期，请重新输入" << endl;
		}
		else
		{
			break;
		}
	}

	return in;
}